Gravity-type roller conveyor with roller driving and roller brake devices

ABSTRACT

A gravity-type roller conveyor includes at least a section thereof in which the rollers are driven by driving members or drivers carried on an endless conveyor belt. The drivers which contact the individual rollers are dimensioned so that their longitudinal width of their outer ends which engage the rollers is less than the spacing between the center lines of the rollers. The conveyor also advantageously includes a braking mechanism in the form of a distance plate or engagement member which is shifted into engagement with a plurality of adjacent rollers along the length of the roller conveyor under the control of an electrical actuating circuit which is energized by a control roller which is located ahead of and/or after the braking device.

United States Patent 11 1 Kiirger et al. Sept. 4, 1973 GRAVITY-TYPEROLLER CONVEYOR 3,127,003 3/1964 Goepper 198/127 R WITH ROLLER DRIVINGAND ROLLER 3,537,568 11/1970 Leach 198/127 R BRAKE DEVICES [75]Inventors: Kurt S. Kiirger, Offenbach/M.;

Norbert F. Axmann, Seligenstadt, both of Germany [73] Assignee: StohrForderanlagen Salzer & Co.

GmbH, Offenbach am Main,

Germany [22] Filed: Aug. 5, 1970 [21] Appl. No.: 61,301

[52] 11.8. CI. 198/127 R [51] Int. Cl. 865g 13/02 [58] Field of Search198/127 R [56] References Cited UNITED STATES PATENTS 2,129,510 9/1938Taylor 198/127 R 2,194,219 3/1940 Eggleston.... 198/127 R 2,622,72012/1952 Lorig 198/127 R Primary ExaminerEdward A. Sroka Att0rney-McGlewand Toren [57] ABSTRACT A gravity-type roller conveyor includes at leasta section thereof in which the rollers are driven by driving members ordrivers carried on an endless conveyor belt. The drivers which contactthe individual rollers are dimensioned so that their longitudinal widthof their outer ends which engage the rollers is less than the spacingbetween the center lines of the rollers. The conveyor alsoadvantageously includes a braking mechanism in the form of a distanceplate or engagement member which is shifted into engagement with aplurality of adjacent rollers along the length of the roller conveyorunder the control of an electrical actuating cir cuit which is energizedby a control roller which is located ahead of and/or after the brakingdevice.

23 Claims, 6 Drawing Figures GRAVITY-TYPE ROLLER CONVEYOR wITII ROLLERDRIVING AND ROLLER BRAKE nEvIcEs SUMMARY OF THE INVENTION This inventionrelates in general to the construction of roller conveyors, and inparticular, to a new and useful gravity-type roller conveyor having aplurality of rotatable rollers for supporting the articles to betransported and a drive belt which is movable below the roll ers andprovided with driving elements thereon at fixed locations along thelength which engage one or more of the rollers during the movementtherebeneath in order to provide a controlled driving movement of therollers for selectively transporting the devices thereover.

In the known gravity-type roller conveyors, the conveyor rollers aredriven by means of an endless belt which extends along the underside ofthe rollers. Such a belt carries a plurality of elongated supportingelements which constantly engage the rollers and provide a driving powerwhich is transmitted to only a few of the conveyor rollers. Theintermittent drive of the conveyor rollers produced in this mannerserves to reduce the dynamic pressure which builds up when the materialto be conveyed piles up in front of a stop for example, at the deliverypoint. A disadvantage of the known conveyors, is however, that thedynamic pressure increases with the number of piled up objects and thedrive belt must be conducted along the rollers to be driven whilemaintaining relatively small tolerances. It has been suggested that inorder to avoid a dynamic pressure build up of the piled up materials,that the belt drive be detached from the rollers. This is done bybringing the drive belt out of contact with the rollers by switchingdevices actuated by the goods to be transported. In a long gravityroller train this requires considerable technical expenditure.

In accordance with the present invention, there is provided a simple andtherefore economical gravity roller conveyor which permits the piling ofthe material under a much lower dynamic pressure and heretofore. Thisproblem is solved according to the invention by providing drivers whichare advantageously of a flexible construction on a conveyor belt andwhich are dimensioned with longitudinal widths which is shorter than thespacing between successive rollers. The driving elements are made longerin a direction perpendicular to the surface of the belt than theshortest distance between the belt and the rollers in order to providethe resilient interengagement of the drivers with the rollers when theyare moved past the rollers. It was found surprisingly, that it ispossible to move articles by means of such drivers which are distributedover the length of the driving belt and which touch the driving rollersonly briefly. Since the friction accurring between the rollers and thedrivers is low there is only a dynamic pressure when the goods arestopped. The drivers may be constructed in the form of upright memberswhich extends substantially perpendicularly or at a slight angle abovethe conveyor belt or they may be formed as loops which are curvedupwardly to a maximum projection from the belt surface at their trailingends. Since the friction between the drivers and the rollers isrelatively low, the loads are gently accelerated when starting fromstand still. At the same time, the electric motor which is generallyused for driving the driver belt is protected against overloads, forexample, when it is necessary to start a conveyor which is alreadyhighly loaded.

The conveyor of the invention advantageously includes a section with abraking device in the form of a distance member or braking plate whichis shifted upwardly to engage a plurality of adjacent rollers in orderto stop their rotation. These braking devices may be used at locationsin which the drivers of the rollers also engage with the rollers sincethe construction of the drivers is such that there is no danger ofdamage to the drivers or the rollers, nor will there be an essentialadditional resistance which loads the driving motor.

Accordingly, it is an object of the invention to provide an improvedroller conveyor which includes rotatable rollers over which the articlesare moved which are selectively driven by driving elements carried on adriving belt, the driving elements having an engagement end which isdimensioned to a longitudinal width which is shorter than a spacingbetween adjacent rollers.

A further object of the invention is provide a roller conveyor in whichthe rollers are selectively rotated by driving elements which are madeof a resilient material and which bear against the rollers at theirperipheries on a side opposite to the load carrying side and which alsoadvantageously includes a braking device in the form of a shiftabledistance plate which is movable into engagement with the rollers at oneside of the conveyor at a location offset from the driving elements, andwhich is advantageously selectively actuated by one or more controlrollers located at either ahead of and/or behind the braking device.

A further object of the invention is to provide a conveyor system whichis simple in design, rugged in construction, and economical tomanufacture.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this specification. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which there are illustrated and described preferredembodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings:

FIG. 1 is a partial longitudinal sectional view of a portion of aconveyor constructed in accordance with the invention;

FIG. 2 is a section taken on the line 22 of FIG. 1;

FIG. 3 is a schematic top plan view of a curved section of the rollerconveyor indicated in FIG. 1;

FIG. 4 is a view similar to FIG. 1, but of another embodiment of theinvention;

FIG. 5 is a schematic side elevational view of a portion of a conveyorhaving an operative braking system; and

FIG. 6 is a partial view of the device indicated in FIG. 5 showing themanner in which the articles are permitted to accumulate at a brakingstation.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to thedrawings in particular, the invention embodied therein in FIGS. 1 to 3includes a gravitytype roller conveyor having a support frame 11 forrotatably supporting a plurality of rollers 12 which are arrangedside-by-side and rotatable freely for the purpose of transportingarticles 50 thereover. The conveyor includes a drive belt 13 which isoperable over a straight section and which carries a plurality ofdrivers or driving elements 160 at selected spaced locations along itslength which may be secured to the belt by means of bolts or screws,etc. The driving elements 160 may be easily replaced or shifted inposition along the belt 13. The upper reach 130 of the conveyor belt 13moves over rollers 14 which can be adjusted in height by means ofadjusting screw mountings 15. The driving elements 16a areadvantageously made ofa resilient material such as a plastic of highwear resistance and they drive rollers 12 from the bottom.

The design and the arrangement of the drivers 16a and the verticaladjustment of the support rollers 14 permit adaptation of the drivers tothe nature of the goods which are to be transported and to the maximumadmissible dynamic pressures which are to be expected.

The drivers 160 are advantageously arranged in groups to provideselected driving effects. The distance or spacing of the drivers fromeach other and the spacing between the groups is arranged in accordancewith the use to which the particular conveyor is to be employed. Thearrangement of the individual drivers in closely spaced relationship ina large group permits the setting in motion of heavy loads of goods, andthese goods are thereafter moved along by the individual widely spaceddriving elements. The drivers which are employed all include verticallyelongated portions such as the drivers 16a in the form of a vane, forexample, which may be deflected or bent backwardly as they pass theirassociated rollers.

A curved section of the conveyor 13 is shown in FIG. 3 which includes aroller track curve 20 with conical rollers 22. A drive belt 23 isarranged below the rollers 2 and is equipped with driving elements 28.The conveyor 23 is arranged along a straight chord through the curve ofthe roller track.

In the embodiment of FIGS. 4, and 5, a drive belt 13 is slidingly guidedover an areal support 24 which, for example, may be a wooden or a metalplate and it is driven by an electric motor 25 as shown in FIG. 5. Thesupport 34 is mounted for adjustable vertical movement to permit it tobe set at a desired elevation for proper engagement of the drivingelements 16b of the conveyor 13 with the associated rollers 12'. Thedriving motor 35 drives the conveyor belt in the direction of the arrow52 and the articles or goods 37 are moved in the direction of the arrow54.

The drivers 16b, which are carried by the drive belt 13, includevertically enlongated loop-shaped portions which extend from a minimumdimension at the forward or front end to a maximum dimension at therearward end to provide for a gradual interengagement thereof with theassociated rollers 12'. The drivers 16b can also comprises tube sectionswhich are secured on the driver belt transverse to the direction of thetube opening, The unique design of the drivers 16b and the fact that thesupport 34 may be adjusted vertically permits a fine regulation of thedriving friction which may be adjusted in accordance with the goods tobe transported and to the maximum admissible dynamic pressures to beencountered.

In accordance with a further feature of the invention braking means areassociated with the conveyor which are advantageously controlled by oneor more switching rollers or control rollers such as the rollers 38 and39. The rollers 38 and 39 are each mounted so that they are biased by anassociated spring 53 and 54, respectively, into a position at which theyproject above the tops of all of the other rollers. Whenever one of thearticles 37 is moved over the associated roller 38 or 39, its associatedspring is tensioned and arm 40 and 41 which supports the roller 38 and39, respectively, is moved into association with a switch 42 or 43respectively. When the goods 37 move over one or the other of therollers 38 or 39, they are pressed down into a position at which theirsurfaces are level with the other rollers as indicated by thepositioning of the roller 38 in FIG. 4. The springs 53 and 54,respectively, pull the arms 40 and 41 into an end position againstassociated stops 44 and 45 respectively, whenever the goods 37 havemoved off these rollers.

At the points where the goods 37 are to be piled up, the braking meansare provided which correspond to the length of the goods to betransported, or longer than the longest piece of the articles which areto be transported. The braking means comprise a plate or distance piece46 having a friction plate or covering 46' and it is supported onparallel pivot arms 47 and 48 which pivot about pivot points 49 and 50,respectively. The arm 48 is made longer than the arm 47 and it issecured beyond its pivot to a plunger 51' ofa solenoid or anelectromagnetic actuator 51. The pressure of the braking plate is soadjusted that its friction force is much greater than that of thedrivers 16b and this ensures that the rollers which are located abovethe friction plate 46' cannot be driven by the drivers 16b. The drivingmechanism 51 is connected through a switch box 52 and at least twoelectrical lines 54 with the associated switches 42 and 43. The switchbox 52 contains the elements necessary for actuating the drivingmechanism 51 and also if necessary, a time delay device and associatedswitching elements.

Several braking devices may be arranged over the length of the entireconveyor and one or two switching rollers or control rollers 38 or 39can be assigned to each braking device. Advantageously one of thecontrol rollers 38 is located ahead of the feed direction and the other39 is located after the braking device.

The piling effect of the gravity roller conveyor can be seen from FIGS.5 and 6. If a pile of goods is formed at the end of the gravity rollerconveyor as indicated in FIG. 5 by a stop 56, the pieces 37a to 37h runup to a block. Since the switching rollers 38 and 29 are actuated, atsome times, simultaneously, the braking distance plate 46 becomeseffective. The trailing piece 371' comes to a standstill on the rollers12', braked by the braking plate 46 and it piles up the followingpieces. This has the affect that only a limited number of pieces pressesagainst the stop 56.

Selection of the number of articles which are to be grouped together foran isolation of some of the articles can be obtained by varying theintervals between the stop 56 and the braking means in the form of thedistance plate 46. With the control of this nature the braking effect iscancelled as soon as one or both switching rollers are free. Theswitches 42 and 43 may be combined to control the driving mechanism 51in such a way that the braking distance plate 46 is brought intoengagement when, and as long as, both of the two switching rollers 38 or39 are engaged by the movement of an article37 thereover.

In H6. 6, there is shown a section of the roller conveyor on whichpieces 37a to 37e are arranged. The pieces 37a, 37b, and 37c move to theright separated by intervals from each other. In order to prevent thefollowing pieces 37d and 37e from moving too close together the brakingdistance plate 46 is actuated so that the respective rollers no longerturn and the pieces 37d and 37e come to a stop. In this arrangement, thebraking distance plate 46 is pressed against the rollers as soon as theswitching roller 39 is pressed down. This has the result that the piecescan only pass individually into the braking zone.

Several driving belts can be arranged side-by-side or several driverscan be arranged side-by-side on a wide driving belt if desired. Separateintermediate rollers driven by the drive belt can also be arranged underthe freely rotating rollers which can serve as driving wheels for thefreely rotating rollers. In addition, the gravity roller conveyors canalso be designed as a caster track. To this end, the drivers 16 mustextend over the entire width of the caster track.

What is claimed is:

l. A gravity-type roller conveyor comprising rotatable rollers overwhich articles are to be moved, support means for said rollers forrotatably supporting said rollers at spaced locations along adefined-trackway, a drive belt movable adjacent the bottom side of saidrollers, a flexible driver on said drive belt movable with said belt andengageable with said rollers thereby to rotate them, said driver beingdimensioned to extend abovesaid belt beyond the bottoms of at least someof said rollers in order to drivingly engage said rollers and having anouter roller engagement surface which is shorter in the drivingdirection than the spacing between adjacent rollers, said drivers beingshaped in the form of a vane.

2. A gravity-type roller conveyor comprising rotatable rollers overwhich articles are to be moved, support means for said rollers forrotatably supporting said rollers at spaced locations along a definedtrackway, a drive belt movable adjacent the bottom side of said rollers,a flexible driver on said drive belt movable with said belt andengageable with said rollers thereby to rotate them, said driverincluding vertically elongated bendable portions being dimensioned toextend above said belt beyond the bottoms of at least some of saidrollers in order to drivingly engage said rollers and having an outerroller engagement surface which is shorter in the driving direction thanthe spacing between adjacent rollers.

3. A gravity-type roller conveyor, according to claim 2, wherein saiddriver includes a vane-like element having a cross section whichdecreases toward the direction of movement of said belt.

4. A gravity-type roller conveyor, according to claim 2, wherein saiddriver is loop-shaped.

5. A gravity-type roller conveyor, according to claim 2, including adrive belt support arranged beneath said drive belt for supporting saidbelt during its movement below said rollers.

6. A gravity-type roller conveyor, according to claim 5, including meansfor adjustably positioning said drive belt support.

7. A gravity-type roller conveyor, according to claim 5, wherein saidsupport comprises a plurality of rollers spaced longitudinally beneathsaid drive belt.

8. A gravity-type roller conveyor, according to claim 2, including aplurality of drivers arranged along the length of said belt, and meansfor securing said drivers on said belt.

9. A gravity-type roller conveyor, according to claim 8, wherein saiddrivers are arranged at equal intervals along said belt.

10. A gravity-type roller conveyor, according to claim 8, wherein saiddrivers are arranged at unequal intervals along the length of said belt.

11. A gravity-type roller conveyor, according to claim 8, wherein saiddrivers are arranged in separated groups along the length of said drivebelt.

12. A gravity-type roller conveyor, according to claim 8, wherein saiddrivers are arranged at s spacing which is different from the spacing ofsaid rollers.

13. A gravity-type roller conveyor, according to claim 8, wherein thereare a plurality of drivers arranged in separated groups, said groupsbeing composed ofa number of drivers which is different from the numberof rollers arranged in a comparable spacing.

14. A gravity-type roller conveyor, according to claim 8, including atleast two drive belts arranged beneath said rotatable rollers andarranged side-by-side.

15. A gravity-type roller conveyor, according to claim 2, wherein saidtrackway comprises a curved trackway said drive belt being arranged on achord of said curved trackway.

16. A gravitytype roller conveyor, according to claim 15, wherein saidrollers of said roller track curve are conical.

17. A gravity-type roller conveyor, according to claim 2, includingbraking means associated with said rollers comprising a distance platesupported below said rollers, and control means for shifting saiddistance plate into engagement with said rollers to stop the rotationthereof in accordance with the position of the goods on said trackway.

18. A gravity-type roller conveyor, according to claim 17, wherein saidcontrol means includes a roller of said rotatable rollers which projectabove all of the other rollers and including means for mounting saidprojecting roller to permit downward movement thereof by the articlepassing thereover to shift said braking distance member.

19. A gravity-type roller conveyor, according to claim 18, wherein saidcontrol means includes a plurality of control rollers arranged alongsaid trackway which projects outwardly from the other of said rollersand which are engageable by the article moving thereover to provide acontrol actuation of said braking distance member.

20. A gravity-type roller conveyor, according to claim 19, wherein atleast two of said control rollers are provided for the controlling themovement of said distance plate one arranged on one side thereof and theother arranged on the opposite side thereof.

21. A gravity-type roller conveyor, according to claim 20, wherein saidcontrol means also includes electrical circuit means connected to eachof said rollers for selectively shifting said distance plate member.

22. A gravity-type roller conveyor, according to claim 21, includingswitching delay means arranged in said electrical circuit for delayingthe operation of said movement of said distance plate member.

23. A gravity-type roller conveyor, according to claim 17, wherein saidbraking distance plate has at least the length of the longest piece ofgoods to be transported on the roller conveyor.

w a a e at

1. A gravity-type roller conveyor comprising rotatable rollers overwhich articles are to be moved, support means for said rollers forrotatably supporting said rollers at spaced locations along a definedtrackway, a drive belt movable adjacent the bottom side of said rollers,a flexible driver on said drive belt movable with said belt andengageable with said rollers thereby to rotate them, said driver beingdimensioned to extend above said belt beyond the bottoms of at leastsome of said rollers in order to drivingly engage said rollers andhaving an outer roller engagement surface which is shorter in thedriving direction than the spacing between adjacent rollers, saiddrivers being shaped in the form of a vane.
 2. A gravity-type rollerconveyor comprising rotatable rollers over which articles are to bemoved, support means for said rollers for rotatably supporting saidrollers at spaced locations along a defined trackway, a drive beltmovable adjacent the bottom side of said rollers, a flexible driver onsaid drive belt movable with said belt and engageable with said rollersthereby to rotate them, said driver including vertically elongatedbendable portions being dimensioned to extend above said belt beyond thebottoms of at least some of said rollers in order to drivingly engagesaid rollers and having an outer roller engagement surface which isshorter in the driving direction than the spacing between adjacentrollers.
 3. A gravity-type roller conveyor, according to claim 2,wherein said driver includes a vane-like element having a cross sectionwhich decreases toward the direction of movement of said belt.
 4. Agravity-type roller conveyor, according to claim 2, wherein said driveris loop-shaped.
 5. A gravity-type roller conveyor, according to claim 2,including a drive belt support arranged beneath said drive belt forsupporting said belt during its movement below said rollers.
 6. Agravity-type roller conveyor, according to claim 5, including means foradjustably positioning said drive belt support.
 7. A gravity-type rollerconveyor, according to claim 5, wherein said support comprises aplurality of rollers spaced longitudinally beneath said drive belt.
 8. Agravity-type roller conveyor, according to claim 2, including aplurality of drivers arranged along the length of said belt, and meansfor securing said drivers on said belt.
 9. A gravity-type rollerconveyor, according to claim 8, wherein said drivers are arranged atequal intervals along said belt.
 10. A gravity-type roller conveyor,according to claim 8, wherein said drivers are arranged at unequalintervals along the length of said belt.
 11. A gravity-type rollerconveyor, according to claim 8, wherein said drivers are arranged inseparated groups along the length of said drive belt.
 12. A gravity-typeroller conveyor, according to claim 8, wherein said drivers are arrangedat s spacing which is different from the spacing of said rollers.
 13. Agravity-type roller conveyor, according to claim 8, wherein there are aplurality of drivers arranged in separated groups, said groups beingcomposed of a number of drivers which is different from the number ofrollers arranged in a comparable spacing.
 14. A gravity-type rollerconveyor, according to claim 8, including at least two drive beltsarranged beneath said rotatable rollers and arranged side-by-side.
 15. Agravity-type roller conveyor, according to claim 2, wherein saidtrackway comprises a curved trackway said drive belt being arranged on achord of said curved trackway.
 16. A gravity-type roller conveyor,according to claim 15, wherein said rollers of said roller tRack curveare conical.
 17. A gravity-type roller conveyor, according to claim 2,including braking means associated with said rollers comprising adistance plate supported below said rollers, and control means forshifting said distance plate into engagement with said rollers to stopthe rotation thereof in accordance with the position of the goods onsaid trackway.
 18. A gravity-type roller conveyor, according to claim17, wherein said control means includes a roller of said rotatablerollers which project above all of the other rollers and including meansfor mounting said projecting roller to permit downward movement thereofby the article passing thereover to shift said braking distance member.19. A gravity-type roller conveyor, according to claim 18, wherein saidcontrol means includes a plurality of control rollers arranged alongsaid trackway which projects outwardly from the other of said rollersand which are engageable by the article moving thereover to provide acontrol actuation of said braking distance member.
 20. A gravity-typeroller conveyor, according to claim 19, wherein at least two of saidcontrol rollers are provided for the controlling the movement of saiddistance plate one arranged on one side thereof and the other arrangedon the opposite side thereof.
 21. A gravity-type roller conveyor,according to claim 20, wherein said control means also includeselectrical circuit means connected to each of said rollers forselectively shifting said distance plate member.
 22. A gravity-typeroller conveyor, according to claim 21, including switching delay meansarranged in said electrical circuit for delaying the operation of saidmovement of said distance plate member.
 23. A gravity-type rollerconveyor, according to claim 17, wherein said braking distance plate hasat least the length of the longest piece of goods to be transported onthe roller conveyor.